Area residents awoke to find temperatures in the low 40s early Monday, and a Canadian blast is expected to plunge the mercury to about 28 degrees by Thursday night, the National Weather Service warned. That's about 15 degrees under the normal low readings for early December in Houston, forecasters said.

The area's record low for that date, Dec. 8, is 27 degrees, which has been reached twice since 1927.

But the freezing temperatures are expected to be short-lived, with Friday's low forecast at 36 degrees and the high expected to reach 52.

Such cold snaps are common for early December, said Patrick Blood, a meteorologist at the weather service's office in League City.

"There's going to be a nice shot of cold air coming down from the north," he said.

Among those who aren't enjoying the weather is Rick Frank, who said he sleeps comfortably on downtown sidewalks most nights but, like many other homeless people, will have to seek a spot in a shelter during this cold snap.

"At night, it's been way too cold, especially about 2 o'clock in the morning," said Frank, 54. "You don't like that."

Staff members at homeless shelters say they're ready for the expected crowds.

"Once the weather turns cold, we see more clients coming in," said Marilyn Fountain, spokeswoman for the Star of Hope shelter near Minute Maid Park.